The aim is to develop a three-dimensional hybridization matrix for oligonucleotide probes that is compatible with microelectronic materials and microanalytical techniques. By using modified inorganic sol-gel-derived materials, the investigators hope to develop a hybridization matrix that covalently bonds to silica (a common material in microfabrication), has a storable liquid precursor, requires no successive washing and depositions, has a quantifiable probe activity, and displays decreased non-specific target adsorption. This will be accomplished by immobilizing probe oligonucleotides on the colloidal particles of a modified silica sol, manipulating the silica sol into or onto the microanalytical device, and then gelling the sol in situ. The surface chemistry of this probe-modified sol is tunable, and the sol should be storable, printable, and have a known activity. Using silanization chemistry, one can modify the properties of the sol to achieve a minimum of non-specific target adsorption and hence increase the sensitivity of the support. Once located in the area of interest, the sol will be made to gel, forming a highly porous solid matrix that provides a higher binding capacity and expanded dynamic range relative to two-dimensional hybridization supports. In short, the investigators seek to develop a filter support that is compatible with the materials and size restrictions of microanalytical systems yet provides exceptional chemical and physical characteristics for hybridization.